Movable steering wheels and steering columns have been features of the automobile industry almost since its very beginning. For example, because of limited space between the steering wheel of the Ford Model T and the seat back and base accessory steering wheels were made available by after-market manufacturers that could be release and swung out of the driver's way upon entering and exiting the driver's seat. Later vehicles included steering columns that could be pivotably adjusted by a small amount to allow greater clearance for the driver between the steering wheel and the driver's seat.
Frequently, as in the case of the movable steering wheel accessory mentioned above, movement of the steering wheel is thought desirable, perhaps necessary, to allow some people to position themselves between the driver's seat and the steering wheel. In such instances movement of the steering wheel is done for practical reasons.
However, in other cases, it is desirable to move the steering wheel forward to the instrument panel to give the appearance of a larger vehicle interior as is often the case with today's increasingly popular smaller vehicle. This impression is particularly important in the vehicle showroom where the potential purchaser may be viewing the vehicle for the first time. In such circumstances the roomier appearance of the vehicle may be more favorably viewed by the driver and potential purchaser.
A number of constraints exist on movement of the steering wheel given passenger safety standards and packaging. With respect to occupant safety, considerations include crash loads (overturning moment) and load vs. displacement selections and the size and configuration of the internal steering components of the steering column. Particularly challenging in the design of an axially movable steering column is the need to separate the stowing or functional travel mechanism from the crash stroking plane.
Known systems for applying axial movement to the steering column fail to overcome the challenges faced both in terms of safety and of packaging. Such systems are limited to a typical axial travel of only about ±25 mm to either side of mid-line at a rate of about between about 10 and 20 mm/sec, making such systems impractical for use in stowing the steering column while the driver is out of the seat then extending the column quickly after the driver is seated. Accordingly, known systems are ineffective at providing convenient steering wheel stowage during normal operation of an autonomous vehicle or at providing steering wheel override by the vehicle operator if an impact event is sensed by the vehicle.
As in so many areas of vehicle technology there is always room for improvement related to stowable steering columns.